Helicopters flew over the Rocky Mountains on Thursday as officials prepare for a “concentrated ground search” for a hiker who has been missing for over a week, the National Park Service said.

Chad Pallansch, 49, of Fort Collins, Colorado, was last heard from on Sept. 27, when a text message indicated he was almost to the summit of Mount Alice in Rocky Mountain National Park, the agency said.

His plans were to hike a 28-mile route, which included established trails as well as off-trail travel, the park service said. He was declared overdue on Sept. 28.

He is 5 feet, 7 inches tall and weighs around 155 pounds, with brown hair and blue eyes, and he is fit, the agency said. He’s a runner with both marathon and trail running experience, it said.

Weather that includes snow, ice and wind has hampered ground efforts, but helicopters flew Thursday in preparation for a “concentrated ground search effort,” the park service said.

Landing zones were being identified where teams could land in the field starting Friday, it said.

Search teams have already been on the ground with dogs, and searches have been conducted by air with heat-sensing equipment, the agency said. Bad weather Wednesday at higher elevations hampered search efforts, it said.